Bishop, 52, has been acquitted of the murders at trial in 1987. However, following a new investigation by Sussex Police and new forensic evidence, the Crown Prosecution Service made a successful application to the Court of Appeal to quash the acquittal of Bishop under the ‘double jeopardy’ law introduced in 2003. To do this, the CPS had to prove to the court that there was new and compelling evidence in the case.

The Court of Appeal ordered a retrial in December 2017 and Bishop was convicted following a trial at the Old Bailey. Together with the new forensic evidence, the prosecution also presented details of the defendant’s movements at the time of the killings, the lies he told police and others, together with his subsequent conviction for a similar attack in 1990, in which a seven-year-old girl was kidnapped and left for dead in Brighton.

Now, the behind the scenes documentary shows how the CPS worked with the police to achieve justice for Nicola and Karen’s families.